class Solution {
2 public:
	3 int tribonacci(int n) {
		4 if (n == 0 || n == 1) return n;
		5 vector<int> dp(n + 1); 
		6 dp[0] = 0, dp[1] = 1, dp[2] = 1; 
		7
			8 
			9 for (int i = 3; i <= n; i++)
			10 dp[i] = dp[i - 1] + dp[i - 2] + dp[i - 3];
		11
			12 
			13 return dp[n];
		14
	}
	15
}